Post on 23-Jan-2021
Isotopes and Animal Movement Seville, 2014
Keith A. Hobson
Primary Goals of Migration
Research
Evolution and Ecology.
Conservation and Management.
Movement of Contaminants and
Disease.
>3M banded,
20% recovered.
>0.8M banded ,
.01% recovered
Problems with extrinsic markers
Organism often needs to be recovered
Expensive
Body size requirements
Biased to original marked population
Biogeochemical processes result in
isotopic patterns or “isoscapes” …
Isoscapes?
Latitudinal/altitudinal gradients (dD, d13C)
Terrestrial-marine (d13C, δ15N d34S) Inshore-offshore (d13C , d34S, d15N) C-3 vs. C-4, CAM (d13C, δD) Xeric vs. Mesic (d13C, d15N)
Surficial geology (Sr, Pb, others)
First isotope applications
Killingley (1980) – δ18O barnacles
“you are what you swim through”
Killingley and Lutcavage (1983)
δ13C and δ18O
From Schell et al.2002
Bowhead whales
Quillfeldt et al. (2010) BES.
Latest marine
isoscapes ….
McMahon et al (2013)
Limnol. Oceanogr. 58:697-714
Predicted locations using correlates
between fish scale collagen (δ13C) and
SST
Mackenzie et al. (2011), Nature.
Mackenzie et al. (2011), Nature
Two essential components:
1. Transfer function (∆) between isoscape
and tissue.
2. Turnover rate of the tissue.
The isotopic clock and movement
Biome 2
Biome 1
dX
(per
mil)
Time (days)
t2 t2’ t1 t1’
Tissue 2
Tissue 1
Heavy isotopes tend not to
fractionate trophically
Stewart et al. MMS 19:806-818
Promise with
Hg isotopes
Point et al. 2011 Nature Geoscience
Strontium (bedrock model)
Rachel Barnett-Johnson
Modeling Sr isotopes in watersheds:
Other applications do not require
use of discrimination factors
Assignment to “bins”
Assignment to “biomes”
Forensic tracing of African ivory ….
δ13C, δ15N, δ87Sr, δ204Pb
Vogel et al. (1990); van der Merwe et al (1990)
Wintering habitat determines arrival time
on breeding grounds
Marra et al. (Science 1998)
Breakthrough with water isotopes
Latest growing-season δ2Hp
Wassenaar, IAEA.
Altitudinal gradients
are recorded in
hummingbird
feathers:
Hobson et al. Oecologia 136:302-308
The feather isotopes follow large
scale trajectories in precip δD
a
Elevation (m)
0 500 1000 1500 2000 2500 3000 3500
dD
(o/ o
o)
-130
-120
-110
-100
-90
-80
-70
-60
b
d1
3C
(o/ o
o)
-28
-27
-26
-25
-24
-23
-22
a
Expected (Ecuador)
Expected (global)
δDf = -25.6 + E(-0.014) -25 o/oo
δDf = -22 + E(0.0224) -25 o/oo
Ecuador:
Global:
More on transfer functions
involving the water isotopes.
Derived from known-origin tissue transects.
Derived experimentally.
Based on various time series (mean annual,
mean growing season).
Can be year-specific or based on long-term
GNIP records.
Single Top Model:
δ2Hf = Int. + δ2Hp + Migratory Guild +
Foraging Substrate + Guild*Substrate
Explains ~83% of the variance in δ2Hf
Dragonfly wing isoscape
Hobson et al. 2012 MEE 3:766-772
Dragonfly fallout on Maldives
Bats …
Cryan et al. 2004. J. Mammal.
Creating basemaps through direct
spatial sampling.
Two populations, one long distance
journey ….
Previously, tagging was used:
Monarchs can be “grown”
anywhere!
80 elementary schools recruited
throughout the range …..
Transfer function derived
experimentally ….
Hobson et al. 1999 Oecologia 120:397-404
Hobson et al. 1999 Oecologia 120:397-404
Transfer function derived from
basemap ….
Hobson et al. 1999 Oecologia 120:397-404
Docykx et al. Ecol. Applic., in press
Origins: 50% of the population is
produced in the US cornblelt:
Assignment depictions
“Map lookup” approach.
Deriving probability of origin
Likelihoods
Bayesian models
• Constrained with priors and other information.
“Leapfrog” migration revealed ..
Kelly et al. (Oecologia 2002)
Other isotopic delineations of
population structure …
Rubenstein et al. (Science 2002)
Bearhop et al. Science 2005
Categorical assignment
Gen
eti
cd
ista
nc
e:
FS
T/(
1-F
ST)
Geographic distance (km)M
igra
tory
dista
nce (k
m)
Origins of Woodpigeons killed in
France
Long-range migrant (winter in southern range of Europe)
Medium-range migrant (winter in France)
sedentary
Several distinct populations with
specific migratory traits
dD precip
-200 -150 -100 -50 0 50 100
Pro
babili
ty D
ensity
0.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
Probability Density0.00 - 0.100.11 - 0.200.21 - 0.300.31 - 0.400.41 - 0.500.51 - 0.600.61 - 0.700.71 - 0.800.81 - 0.900.91 - 1.00
Probability Density0.00 - 0.100.11 - 0.200.21 - 0.300.31 - 0.400.41 - 0.500.51 - 0.600.61 - 0.700.71 - 0.800.81 - 0.900.91 - 1.00
Probability Density0.00 - 0.100.11 - 0.200.21 - 0.300.31 - 0.400.41 - 0.500.51 - 0.600.61 - 0.700.71 - 0.800.81 - 0.900.91 - 1.00
A)
B)
Conditional Probability
0.000000 - 0.000001
0.000002 - 0.000002
0.000003 - 0.000003
0.000004 - 0.000015
0.000016 - 0.000064
0.000065 - 0.000070
0.000071 - 0.000625
0.000626 - 0.000685
0.000686 - 0.005397
0.005398 - 0.006830
A
B
C
D
E
F
G
H
I
J
Conditional Probability
0.000000 - 0.000001
0.000002 - 0.000002
0.000003 - 0.000003
0.000004 - 0.000015
0.000016 - 0.000064
0.000065 - 0.000070
0.000071 - 0.000625
0.000626 - 0.000685
0.000686 - 0.005397
0.005398 - 0.006830
Conditional Probability
0.000000 - 0.000001
0.000002 - 0.000002
0.000003 - 0.000003
0.000004 - 0.000015
0.000016 - 0.000064
0.000065 - 0.000070
0.000071 - 0.000625
0.000626 - 0.000685
0.000686 - 0.005397
0.005398 - 0.006830
A
B
C
D
E
F
G
H
I
J
Origins of Woodcock taken in
Spain
Applying prior probabilities
Royle and Rubenstein
Combining genetics and δD
Boulet et al. (Ornithol Monogr)
Modeling isoscapes and origins
using multiple isotopes
Assumes a multivariate normal distribution
All isotopes are orthogonal
Africa has a rich history of stable
isotope applications
Major overwintering site for
Palearctic-Aftrotopical migrants
Plant isotope distribution models
Plant isotope map
based on predicted C3
vs. C4 plants
Still and Powell (2010)
Feather δ13C isoscape
A feather δ15N isoscape Based on Craine et al. (2009, New Phytologist)
Modeled MAT, MAP with foliar δ15N
Modeled MAT, MAP with foliar and soil
δ15N
Feather δ15N isoscape
Feather δ2H isoscape
Combining δ13C, δ15N, δ2H feather
isoscapes
Pied Flycatcher
Collared Flycatcher
Data from Hjernquist
A multi-isotope (δ2H,δ13C,δ15N)
probability surface
Some other considerations and
future directions….
Several controlled studies for δ15N,
δ13C but few for δ2H, δ18O ….
δ15N, δ13C …
δ2H, δ18O …
Using a wind tunnel and isotopic
dietary shifts to mimic migration
Max Planck Institute for Ornithology
Advances in water isoscapes
Multiple sources of O and H
Pietsch et al. 2011 PLoS ONE
Pietsch et al. 2011 PLoS ONE
Pietsch et al. 2011 PLoS ONE
Oxygen?
20-35%
evaporative loss
Human Hair
Ehleringer et al. (PNAS 2008)
Meteoric relationship preserved in
Monarch Butterflies
Manitoba
Indiana
Florida
y = 7.951x - 123.948
R2 = 0.936
-140.0
-130.0
-120.0
-110.0
-100.0
-90.0
-80.0
-70.0
-60.0
-2.5 -1.5 -0.5 0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5
dO18
smow(Pyrolysis)
dD
sm
ow(P
yro
lysis
)
Feather 18
O (per mil)
6 8 10 12 14 16 18 20 22 24
Feath
er
2H
(per
mil)
-140
-120
-100
-80
-60
-40
-20
Y = -145.7 + 4.8X
r2 = 0.34
Trace element/heavy isotope
Compound specific
Mass spectrometry